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REM sleep behavior disorder is related to a type of dream state in which a person dreams that someone is attacking them and that they have to fight them off.

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January 2, 2019

For people with REM (rapid eye movement) sleep behavior disorder, violent actions, such as punching, kicking, and yelling, can be a recurring part of their nightly slumbers. But who is most at risk for the condition and why?

“The most important thing about REM sleep behavior disorder is not the sleep disorder itself, it’s the fact that it’s an early sign of Parkinson’s disease and related disorders [such as Lewy body dementia],” says study author Ronald Postuma, MD, of McGill University in Montreal, Canada, and a member of the American Academy of Neurology.

Dr. Postuma estimates that about 1 percent of the general population over age 50 have this sleep condition, and 80 percent of those who develop REM sleep behavior disorder (RBD) will go on to get Parkinson’s, a progressive disease of the nervous system that affects movement.

“That’s why we’re studying the disorder,” he says. “Identifying risk factors linked to this sleep disorder may lead to finding ways to reduce the chances of developing it.”

'Quite a Dramatic Situation' and Dangerous

About 20 percent of nightly sleep is spent in the REM stage, when people dream and their body experiences a normal temporary paralysis, according to the Mayo Clinic. For individuals with this violent sleep condition, the normal brain signals are disrupted, causing them to physically act out their dreams.

“It can develop into getting out of bed, fighting an imaginary foe in the corner of the room, and actually throwing things,” says Thomas Kilkenny, DO, director of sleep medicine at Staten Island University Hospital in New York, who was not involved in the study. “It can be a quite dramatic type of situation. When you talk to a patient, the disorder is related to some type of dream state. They’re dreaming someone is attacking them and the patient is fighting off this foe that is in this dream.”

Marc Raphaelson, MD, a fellow of the American Academy in Neurology who was also not involved with the research, adds, “People who punch and kick during sleep sometimes also hurt themselves or loved ones in the same bed. I have treated combat veterans who have RBD in addition to PTSD [post-traumatic stress disorder], and their dream-enacted aggressive behavior can be dangerous.”

How the Study Was Conducted

Postuma and his colleagues reviewed 30,097 Canadian adults between ages 45 and 85 who had participated in a large study on aging; the average age was 63. Participants were screened for a variety of health conditions and answered questions about lifestyle, behavior, social, economic, and psychological factors.

RBD was identified by those who answered “yes” to the question: "Have you ever been told, or suspected yourself, that you seem to ‘act out your dreams’ while asleep (for example, punching, flailing your arms in the air, or making running movements)?"

For accuracy, investigators excluded patients with apnea or early-onset dream enactment behavior, which is most likely not RBD. They also did not include those who had already developed Parkinson’s disease, dementia, or Alzheimer’s disease.

Signs of REM Sleep Behavior Disorder

“We found some persistent associations between possible RBD and mental health issues, which will need to be confirmed in clinical studies,” says Chun Yao, PhD, study coauthor and student with the Integrated Program in Neuroscience at McGill University.

Investigators noted that those with the disorder were twice as likely to report taking antidepressants. A total of 13 percent with RBD took antidepressants, as compared with 6 percent without the disorder.

Mental illness was twice as common among those with the disorder, psychological distress was one-and-a-half times as likely, and post-traumatic stress disorder was two-and-a-half times as likely.

The study’s authors also observed that men were twice as likely to have the condition compared with women (59 percent versus 42 percent). Moderate to heavy drinkers had 25 percent greater odds of having RBD.

Those with the disorder also had a slightly lower average level of education (13.2 years versus 13.6 years), and they were more likely to have a lower income (17.3 percent versus 15.9 percent). Those who reported having smoked in the past had increased chances of having the disorder (42.7 percent versus 36.9 percent) as did current daily smokers (8.9 percent versus 6.4 percent).

Postuma stresses that the results do not show that the risk factors cause REM sleep behavior disorder, they only show that they are linked.

A Step Toward Treating Parkinson’s?

Dr. Kilkenny points out that the sleep disorder itself may be treated with a medication, such as Klonopin (clonazepam), which calms the brain and nerves. He advises that people with signs of RBD should consult a doctor, neurologist, or sleep specialist.

Still, Postuma cautions that treating the sleep disorder may not prevent a patient from developing Parkinson’s.

“We’re going to have a preventative treatment for Parkinson’s at some point, so it’s going to be really important to find people early,” says Postuma. “This study shows one way to find people early.”

Postuma, Chun, and their fellow researchers plan to continue following the patients with RBD and see what signs of neurodegeneration may develop among them.

Study authors note that the investigation was limited by the fact that 96 percent of the participants were white, so the results may not apply to other ethnic backgrounds. RBD symptoms were also self-reported rather than documented through a sleep study. Still, the large volume of participants lends strength to the report, according to Kilkenny.